Blender Old UV applied on top of new UV
I assume the problem is this:

This flickering can have a few reasons, in your case it is an accident that happened while modelling. You duplicated that wall and left the duplicate in the same place. It has a different UV Map than the original, so both walls try to show their (different) texture to the viewer, resulting in a heavy fight.
To resolve it, delete one of the walls. Select one arbitrary face, and run the Select Linked command. Then delete those selected faces:

Do this for all problem walls, and make sure to check the ones that seem right as well. As long as the UV Map is identical, you might not spot the issue at all.